Myxomatosis myxoma virus - a threat to wild and domestic rabbits Pet Diseases abroad Myxomatosis Myxomatosis is caused by the myxoma virus, a type of pox virus that only affects rabbits. It was first discovered in 1896 in Uruguay and was imported to Australia in 1951 to control its large rabbit populations - initially having the desired devastating effect. The disease was illegally introduced to France in 1952 and it appeared in Britain the following year. It quickly spread to both wild and domestic rabbit populations and within a few years had spread throughout Europe. Myxomatosis has been a threat to wild and domestic rabbits ever since. Who is at risk? All rabbits, whether wild or domestic are at risk of myxomatosis. How is it spread? Myxomatosis is typically spread by blood sucking insects and in particular the rabbit flea, Spilopsyllus cuniculi. This flea is frequently found on wild rabbits and transmission in the absence of bites is unusual. All breeds of domestic rabbit can be affected, with little to suggest that one breed is more susceptible than another, and whatever the lifestyle of your rabbit there is a potential risk of this disease.

Signs and symptoms The incubation period varies depending on the strain and its virulence and is typically at least five days. Accompanying the classic bulging eyes that most of us associate with myxomatosis, are localised swellings around the head, face, ears, lips, anus and genitalia. Severe swellings can lead to blindness and distortion around the face within a day or so of the onset of symptoms, leading to difficulty with feeding and drinking. Bacterial respiratory infection often complicates the disease resulting in a fatal pneumonia. Progress of the disease may be slower in well cared for pet rabbits and recovery is sometimes possible with intensive care. However, myxomatosis can be a very protracted and profoundly unpleasant disease and euthanasia is generally recommended. Recovery in the wild occasionally occurs but for animals with severe signs death usually occurs about 12 days after initial infection. Management of myxomatosis There is no specific treatment for the virus and any treatment offered is merely supportive. Treatment is occasionally contemplated but would not usually be recommended for rabbits with the full-blown disease since affected individuals suffer dreadfully, have a low chance of survival and they remain a source of infection for other rabbits.

The occasional individuals with milder disease may, however, recover with appropriate care. Control of myxomatosis To help prevent your rabbit from contracting myxomatosis, it is important to put various controls in place, for which there are two main methods: control of parasites and vaccination. Flea control Always keep a regular check on pets for any signs of fleas and consider the regular use of an insecticidal treatment from your vet. There is also evidence to suggest that mosquitoes and other biting flies may transmit myxomatosis in the UK, so nets and insect repellent can be used to combat this threat in warmer weather. Your vet will be able to advise you further on these measures, since not all products are suitable or safe for rabbits. Vaccination A dual vaccination covering both myxomatosis and rabbit haemorrhagic disease (RHD) has recently been launched in the UK and is designed to replace the older myxomatosis-only product during 2012.

This new vaccine provides efficient and effective protection of rabbits against both diseases Vaccination schedule It is recommended that a single dose of the new vaccine is given to all rabbits over the age of five weeks and requires an annual booster to maintain protection Strains of myxomatosis and vaccine development Although myxomatosis is typically fatal in rabbits without immunity, there are many different strains and some are more virulent than others. As evolution has progressed and the virus adapts accordingly, the modern myxoma virus which causes the disease may not always kill rabbits quite as readily or rapidly as older strains, although the disease continues to have a very high mortality associated with it in pet rabbits. Previously vaccination in the UK used the related but non-disease causing Shope fibroma virus which was well proven in terms of safety and but also was similar enough to the myxoma virus to give useful levels of immunity. Attempts at producing inactivated (killed) myxomatosis vaccines have proved ineffective. Other approaches that have been taken abroad with mixed results have included using a weakened strain of the myxoma virus as a vaccine.

The new vaccine is based on a novel approach disabling the myxoma virus in a way that renders it unable to cause disease but preserving its ability to providing effective protection not only against myxomatosis but also uniquely giving it the ability to protect against the equally serious rabbit haemorrhagic disease (also known as rabbit haemorrhagic disease or RHD) Can rabbits contract myxomatosis after vaccination? Vaccination can never guarantee 100% protection against any disease. However, when used as recommended in healthy rabbits, the new vaccine has been shown to be very effective at preventing this dreadful disease for a full 12 months representing significant advance over the older product. Vaccination may sometimes appear ineffective if given to rabbits already incubating the disease, or those whose response to vaccination can be impaired by underlying health problems, poor nutrition, genetic factors, severe stress and drug therapy. For these reasons it is always important to consider other steps to reduce the risk of infectious disease. These include the control of fleas and other external parasites and steps to prevent exposure to flies in hutches and runs.

It is also important to avoid contact between domestic and wild rabbits and to ensure good basic husbandry and feeding to reduce the risk of potential health problems and associated stresses. Your veterinary surgeon will be able to advise on a care plan for your rabbit which can address all these issues. In addition, control of fleas, good basic husbandry and steps to reduce stress should be undertaken to reduce the risk of myxomatosis and complement the protection afforded by vaccination. Rabbits - Infectious Disease | VCA Animal Hospital Rabbits - Infectious Disease Infectious Diseases, Zoonosis & Human Health December 13, 2008 There are 4 major infectious diseases seen in pet rabbits. Two serious diseases caused by viruses may occur in rabbits, although they are rarely seen in indoor pets. They are myxomatosis and viral hemorrhagic disease. Because they are viral diseases, there are no effective treatments once the rabbit is infected. Two other infectious diseases of rabbits are Encephalitozoan cuniculi and Pasteurella multocida. Myxomatosis This is caused by the myxoma virus, which is widely distributed in the wild rabbit population.

Even if your rabbit never comes into direct contact with animals from the wild, it can still become infected with this disease. This is because the virus is spread by bites from mosquitoes, flies, fur mites and fleas. It is also acquired from contaminated thorns or thistles, or by direct contact with an infected rabbit. It is found in North America (primarily California), South America, Europe and Australia. Pet rabbits are more susceptible and more severely affected than wild rabbits, as wild rabbits have developed a better genetic resistance. Clearly, outdoor rabbits are at greater risk of getting this disease. The incubation period is 1-3 days and the first signs are the development of puffy eyelids, a purulent (pus-producing) conjunctivitis, and lethargy. Subcutaneous swelling (swelling under the skin) extends around the eyes, ears and genital region. This can rapidly progress to skin hemorrhages, trouble breathing, inappetence or anorexia, swelling around the base of the ears, fever, and development of generalized skin tumors. Death is usually within 1-2 weeks after infection, but occasionally animals will survive and signs will slowly regress over about 3 months.

"Clearly, outdoor rabbits are at greater risk of getting this disease." Vaccination may provide temporary protection. This vaccine is not available in some countries. Pregnant animals should not be vaccinated, nor should rabbits less than six weeks old. Occasionally there is a local reaction at the injection site, but compared with the lethal infection, this is insignificant. Viral hemorrhagic disease Also called Rabbit CaliciVirus (RCV); Rabbit Hemorrhagic Disease (RHD); and Viral Hemorrhagic Disease (VHD), this highly contagious disease was first recognized in China in 1984 but now has an almost worldwide distribution. Viral hemorrhagic disease is caused by a calicivirus and, although the incubation period is up to three days, animals may die suddenly without any clinical signs. The disease is transmitted by direct contact with infected rabbits, rabbit products, rodents, and contamination of cages, dishes, and clothing. The virus can also transmit over short distances in moist air. Rabbits in close proximity to other rabbits (such as breeders, rabbit shows) are at a greater risk. Rabbits that recover can become carriers of the virus and may shed virus up to 4 weeks.

If there are signs, they include anorexia (not eating), pyrexia (fever) apathy and prostration. There may be convulsions and coma, dyspnea (difficulty breathing), foaming at the mouth, or a bloody nasal discharge. Some animals survive this acute phase but die a few weeks later from liver failure. "Highly contagious disease was first recognized in China." Given the horrendous death experienced by affected rabbits, consideration should be given to vaccinating pet rabbits annually (or even as often as every six months) in areas where the disease is rampant. Vaccines are not available in every country; they will not eradicate the disease, but may reduce the number of deaths. Speak to your veterinarian about vaccine availability in your area, and the risks and benefits of its use. New rabbits should be isolated from other rabbits for 30 days to minimize the risk of this infection. Encephalitozoan cuniculi (E. cuniculi) E. cuniculi is a small microsporidian parasite that is intracellular, or has to live within a cell. It can affect rabbits, mice, hamsters, dogs, cats, guinea pigs and humans.

It usually causes a latent condition in rabbits, meaning that most infected rabbits will show no symptoms. When symptoms do develop, the affected rabbit may develop heavy white cataracts in one or both eyes or a head tilt; the disease can progress and produce more severe signs such as twitching eyes (nystagmus), anorexia, difficulty walking, tremors and seizures. The cataracts can be surgically removed. Otherwise, there are currently no particularly effective drugs to treat the disease; however, this may change in the near future as different drug protocols being used with various degrees of success. "This underlines the importance of always washing your hands after handling any animal and before eating or preparing food." Encephalitozoonosis has been described in a few cases in people, but its significance is poorly understood. Very young, elderly and immunocompromised people are most at risk. This underlines the importance of always washing your hands after handling any animal and before eating or preparing food. Pasteurella multocida Pasteurella multocida is a bacterial organism that commonly causes abscesses and chronic inflammatory disease in rabbits.

It can infect the nasolacrimal (tear) duct, eyes, ears and nose, and can cause abscesses of tooth roots, bones (particularly the mandible or jaw), skin (or just under the skin) and/or internal organs. A very common problem associated with the organism is an upper respiratory tract infection called snuffles; snuffles usually occur in young rabbits. Most cases of snuffles are mild and, if caught early, can be effectively treated or managed. If left untreated or if the strain of bacteria is particularly aggressive, this disease can be severe, chronic and potentially fatal. A swab sample for bacterial culture can be taken to help guide treatment. Treatment usually involves either oral or injectable antibiotics, given for a minimum of 2 - 4 weeks. In some cases, treatment can be required for months (or rarely for years) depending on the response to therapy. Certain oral antibiotics, especially oral penicillin and similar drugs, can be fatal to rabbits. There are some excellent oral and injectable antibiotics for use in rabbits with this infection, but none is a sure cure. Eye drops and nose drops may be used in conjunction with other antibiotics as prescribed by your veterinarian.

"If left untreated or if the strain of bacteria is particularly aggressive, this disease can be severe, chronic and potentially fatal." Surgery is possible may be advised if the abscess is in or under the skin; abscesses of the middle ear (causing balance problems), in the eyeball (causing blindness), in the mandible (jaw bone) or in the internal organs, are less easy to treat. All rabbits carry some Pasteurella organisms, but only some show or manifest disease (the immune system generally keeps the organisms in check). Stresses such as improper diet, new diet, change in diet, introduction of a new pet, overcrowding, environmental stresses, immunosuppression or other disease may trigger clinical disease. Many rabbits become are chronically infected. The disease is easily transmitted by close contact between rabbits but remember that not all rabbits will manifest disease. Ideally, new rabbits should be isolated (for about one month) before introducing them to existing pets. Relapses may occur if your rabbit is exposed to stressful situations. It is important to keep your rabbit as healthy as possible to minimize problems with pasteurellosis.

This client information sheet is based on material written by: Rick Axelson, DVM © Copyright 2009 Lifelearn Inc. Used and/or modified with permission under license. Myxomatosis - WikiVet English Myxomatosis Created by the veterinary profession for you - find out more about WikiVet Did you know you can edit or help WikiVet® in other ways? Also known as Rabbit Pox A European Rabbit afflicted by Myxomatosis Source: Wikimedia Commons; Author: Chris Bayley, 2007 Contents 8 References Introduction Myxomatosis is a highly contagious viral condition of rabbits caused by the myxoma virus, a member of the poxvirus group. It was first recognised in the UK in 1953 after it crossed the channel from France where it was illegally introduced in 1952. It is carried mainly by arthropods, particularly the rabbit flea, Spilopsyllus cuniculi. The disease is also transmitted by direct or indirect contact with ocular or skin discharges or by mechanical vectors. The disease is characterised by subcutaneous mucinous lesions and nodular tumours and is associated with a high mortality rate.

Myxomatosis is enzootic in cottontail rabbits of the genus Sylvilagus in both South and North America and in wild rabbits of the genus Oryctolagus in South America, Europe, and Australia. All other animals are resistant to the disease. Pathogenesis The myxoma virus infects several cell types including mucosal cells, lymphocytes and fibroblasts. In addition to primary and secondary tumour development, there is severe immunosuppression leading to overwhelming infections by opportunistic gram-negative bacteria particularly affecting the conjunctiva and nasal passages. Virus multiplication and tumour-like lesions occur initially at the site of intradermal inoculation. This is followed by spread to regional lymph nodes and cell-associated viraemia, with generalization to the skin and internal organs. Gelatinous proliferative nodules develop all over the body, especially at orifices such as the eyes, anus, nose. There are three known forms of disease manifestation: Acute Form: this becomes apparent three days after experimental infection: oedema of the head, eyelids and genitals, followed by the appearance of myxomes.

This form is usually fatal and death occurs wihtin 14 days (Okerman 1994). The chronic, nodular form shows oedematous swellings called pseudotumours which develop after 10-15 days on the ears, nose and paws and is not so fatal (<50%) but mean survival time is 40 days (Okerman 1994). Lesions develop into hard scabs which heal into scars and sometimes can even lead to holes “punched” through the pinnae. This is the form that occurs in vaccinated animals may be worth treating in pet rabbits – oxytetracycline (Engemycin 5%®; Intervet) SC q 72hrs, good feeding and prokinetics if the gastrointestinal system seems compromised. A specialised form is seen in Angoras which have been vaccinated and then depilated: Lesions can be found on the torso only in animals with waning immunity after vaccination and are considered to be a type IV hypersensitivity reaction (Ganiere et al 1990).

Epidemiology The disease is transmitted by both direct and indirect means (Okerman 1994), the former principally involving contact with infected wild rabbits; the latter, with arthropod vectors, including fleas, lice and mosquitoes, although (Gaguere 1995) implied that the mosquito is the only vector worth considering. The incubation period of the virus is two to eight days, and the duration of illness is usually from eleven to eighteen days. Pyrexia (42ºC) is a feature of the disease at or around the second day. Death is inevitable and is usually due to secondary infection with Pasteurella spp (Harkness and Wagner 1989) which is also why some cases seem to respond initially to antibiosis. Clinical signs The clinical disease varies with the virus strain and host species. Lepus species (hares are highly resistant; occasional individuals develop mild to severe generalized myxomatosis. Sylvilagus species are relatively resistant and are probably the natural host of the virus. In this species, infection usually results in the development of skin tumours at the site of innoculation.

The tumours appear 4-8 days after exposure and persist for up to 40 days. In the European rabbit (Oryctolagus cuniculus), infection with a virulent virus (i.e. the South American or California strains) results in severe disease with up to a 99% case fatality rate. Initial signs include oedema of the eyelids accompanied by inflammation and oedema of the anal, genital, oral and nasal orifices. Oedema of the head and ears, drooping ears and bacterial infections resulting in mucopurulent conjunctivitis and pneumonia are seen. Severe pyrexia is frequently reported. Death (8-15 days post infection) is usually preceded by dyspnoea and seizures. The mortality rate is affected by environmental temperature, with the disease being more lethal at low temperatures. Pathology The most prominent gross lesions in European rabbits with myxomatosis are the skin tumours and the pronounced cutaneous and subcutaneous oedema, particularly in the area of the face and around body orifices. Skin hemorrhages and subserosal petechiae and ecchymoses may be observed in the stomach and intestines.

Subepicardial and subendocardial hemorrhages may also occur. Adult rabbits of the genus Sylvilagus usually develop localized skin tumours resembling fibromas. Hares or young Sylvilagus rabbits may develop fibromatous to myxomatous nodules, however, lesions are usually mild and localized. Prevention Vaccination and control of insect parasites are the most important means of disease prevention in domestic rabbits. In order to control fleas, wild rabbits should be kept away from pet rabbits and spot-on products may be used. Mosquito control can be achieved using insect repellent strips and fine mesh netting. The use of Vapona® strips and Nuvan Top® to prevent fly strike and myxomatosis is recommended (Lawton 1993). Rearguard® (Novartis) has a licensed place in the prevention of fly-strike. Permethrin sprayed on mosquito netting to cover hutches has been recommended.

The myxomatosis vaccine currently used in the UK is a live vaccine containing Shope fibroma virus (Nobivac Myxo, Intervet) - Shope's fibroma virus causes fibromatosis, a benign disease of Sylvilagus loridanus, an American lagomorph species. Antibodies made against Shope fibroma provide cross immunity against myxomatosis for three months. Intradermal vaccination is performed in order to achieve adequate immunity and annual booster vaccination is recommended; the manufacturers advise revaccination every six months in the event of "high risk" exposure. Live attenuated vaccines have been used elsewhere in Europe but have been associated with other side effects such as immunosuppression. Note on “Shopes Viruses” Shope fibromavirus and Shope Papillomavirus (two distinct viruses) have dermal manifestations but are rare in the UK. Note the vaccine, Nobivac Myxo®; Intervet, contains the Shope Fibroma virus and is used to confer immunity against myxomatosis in rabbits in the UK. Shope papillomatosis is manifested mostly on the eyelids and ears as a pedunculated cornified surface over a fleshy central area.

Spontaneous outbreaks have been recorded in domestic rabbits. Pedunculated cornified surface overlying a fleshy central area. After manual removal of the lesions, can extend to squamous cell carcinoma. Probably vector-spread (Meredith 2006). Papillomata on eyelids and ears. (Percy and Barthold 1993) Shope fibromavirus, the cause of Rabbit (Shope) Fibromatosis, leads to flattened, firm, subcutaneous, freely movable tumours (=/<7cm diameter) on legs and feet sometimes on the muzzle and periorbital and perineal areas, and may persist for several months. In young rabbits metastasis to abdominal bone marrow and abdominal viscera may occur.

(Percy and Barthold 1993) Treatment Although the mortality rate in affected rabbits is high, recovery is possible and treatment can be worthwhile: Increase ambient temperature to 29.5°C - the virus is more virulent at lower ambient temps Antibiotics that combat pasteurellosis, procaine penicillin (SC q 3-4d) or oxytetyracycline (SC q72h) “Good nursing“ pro-kinetics if you can get them NSAID's There are anecdotal reports of the use of Interferon in myxomatosis - some cases recovered and some didn't. Did the ones that recovered receive the dose prior to clinical signs? How would you know that the rabbits were going to get the disease? Were they going to recover anyway, in spite of treatment? Rabbits that had full-blown clinical signs didn't recover, even when given Interferon. There were, apparently, no bad side-effects as a result of administration of interferon and clients might appreciate that the clinician was doing his best to help sick or in-contact rabbits.

Myxomatosis is spread rather erratically by contagion, more by vectors, so the use of “preventative treatments” (interferon or vaccination) in the face of an outbreak is difficult to justify. In-contact rabbits might not be actually incubating the disease as they might not be infected yet and therefore the vaccine has a better chance of working. If they are already incubating the disease the vaccine won’t work so there is definitely no benefit if clinical signs are established and no point using it as a therapy. Myxomatosis Learning Resources myxomatosis | animal pathology | Britannica.com animal pathology Alternative Titles: infectious myxomatosis, myxomatosis cuniculi, rabbit pox Similar Topics curly top Myxomatosis, formally infectious myxomatosis, or myxomatosis cuniculi, a highly fatal infectious viral disease of rabbits. It is characterized by fever, swelling of the mucous membranes, and the presence of nodular skin tumours. The disease exists naturally in populations of certain South American rabbits of the genus Sylvilagus and has been introduced into western Europe and Australia as a means of rabbit population control.

Learn More in these related articles: in community ecology: Parasite-host interactions The evolution of myxoma virus in rabbits in Australia shows how quickly coevolution of parasites and hosts can proceed to a new outcome, in this case intermediate virulence. European rabbits were introduced into Australia in the 1800s. In the absence of parasites and predators that had kept their numbers in check in their European habitat, they multiplied and disseminated rapidly, causing... in rabbit: Natural history ...damage to crops and decreases—even extinctions—of native Australian flora and fauna the result. Attempts to control the rabbit have been largely futile. For instance, a viral disease (myxomatosis) naturally existing in certain South American cottontails was found to be lethal to European rabbits. The virus was introduced to the Australian population during the early 1950s, and... 2 References found in Britannica Articles Assorted References Corrections? Updates? Help us improve this article! Contact our editors with your feedback. MEDIA FOR: You have successfully emailed this. Error when sending the email. Try again later. Edit Mode Submit Tips For Editing We welcome suggested improvements to any of our articles.

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Close Date Published: December 08, 2006 URL: Access Date: December 18, 2016 Share Myxomatosis in Rabbits: Transmission, Signs, Diagnosis, Treatment, Prevention Myxomatosis in Rabbits: Transmission, Signs, Diagnosis, Treatment, Prevention Veterinary & Aquatic Services Department, Drs. Foster & Smith What is myxomatosis? Myxomatosis is a viral infection of rabbits, caused by a member of the Poxvirus family. It is usually transmitted by insects and is usually fatal. In the United States, myxomatosis is most commonly seen along the Pacific coast. There are several strains of the virus. The virus that is present in the Western USA is referred to as the California strain of myxoma virus and possesses characteristics that differ slightly from other strains. California strains have been known to cause over 99% mortality. The myxoma virus was introduced into Australia in 1950 and Belgium in 1953 in an attempt to reduce the population of wild rabbits.

With time, the virus became less pathogenic (less able to cause disease) and in Australia, the mortality rate dropped to approximately 25% compared to over 90% when the virus was first introduced. How is myxomatosis spread? Blood-sucking insects, including mosquitoes, fleas, lice, ticks, and mites, are the main method of spread. Direct transmission is possible, usually by the aerosol route. Those rabbits infected via this route usually develop nasal & eye discharges as part of the disease process. Transmission is also possible via infected hutches or enclosures. An owner may spread the virus from one rabbit to another. Similarly, animals that are congregated at rabbit shows or fairs may become infected if one of the rabbits has the disease and is shedding the virus. What are the signs of myxomatosis? The clinical signs of myxomatosis vary with the strain of virus involved and the species of rabbit infected. In pet rabbits, there are several forms of the disease. Peracute form: The peracute form progresses most rapidly and may cause death within 7 days of infection, and within 48 hours of showing signs of disease.

The only signs may be lethargy, swelling of the eyelids, loss of appetite, and fever. Acute form: In the acute form, fluid accumulates under the skin, causing swellings around the head and face, including the lips, nose, and around the eyes. The swelling around the eyes gives the rabbit a sleepy appearance. Swellings of the ears may cause them to droop. The area around the anus and genitalia also appears swollen. The lesions progress rapidly, and within 24-48 hours may become severe, causing blindness. The rabbit continues to have a fever and be depressed. Most rabbits die of hemorrhage and seizures within 10 days. In a susceptible population, over 90% of rabbits may die in this stage of disease. Chronic form: The chronic form of the disease is less common, and occurs in animals that survive the acute form of the disease. Rabbits with this form develop thick ocular (eye) discharge and swelling around the base of the ears. Nodules called "myxomas" may develop, although with infection by the California strain of virus in domestic rabbits, myxomas are seldom present in infected animals.

Affected rabbits may also show respiratory signs including difficulty breathing. Most animals die of the disease within two weeks. Rabbits that survive may shed the virus up to 30 days. Most rabbits who recover from myxomatosis are immune to re-infection for the rest of their lives. How is myxomatosis diagnosed? The diagnosis of myxomatosis is made through observing the clinical signs, biopsies of the lesions, and virus isolation. In many cases, because the rabbit dies suddenly, the diagnosis is made post-mortem (after death). How is myxomatosis treated? There is no effective treatment for myxomatosis. Affected rabbits may be kept more comfortable through the use of supportive fluids. How is myxomatosis prevented? The best way to prevent myxomatosis is to control external parasites such as mosquitoes, fleas, and mites. Screening should be used to protect outside animals. Rabbits should be kept indoors, if possible, especially during the peak insect seasons of the year, and at dawn and dusk, when many insects, such as mosquitoes, are more active. If a rabbit is suspected of having myxomatosis, the animal should be isolated and mosquito netting placed over the cage.

Extreme care should be taken to prevent mechanical transmission to other rabbits through dishes, contamination of clothing, or other means. The myxoma virus is resistant to inactivation under most environmental conditions and is not easily destroyed by disinfectants. If a rabbit is exposed to an infected animal, she should be quarantined for a period of 14 days. During the quarantine, she should be handled as though she were infected and cared for as indicated above. After 14 days, if the rabbit does not become sick or develop a fever greater than 102.5°F, it can be assumed she is not infected with the myxoma virus. If myxomatosis occurs in an area, rabbits should not be taken to fairs, rabbit shows or anywhere these animals are congregated. A vaccine has been developed (an attenuated modified-live virus) against myxomatosis, but is not available in the United States. MediRabbit Sanarelli first recognized the myxomatosis disease in 1896, in Uruguay, where it causes sporadic lethal infections in the American cottontail species (Sylvilagus sp.).

The virus has spread over the entire American continent, and has become endemic in some regions (Chili, in O. cuniculi; Western USA, in Sylvilagus bachmani). MediRabbit Common form of myxomatosis, with the development of facial myxoma. It was soon discovered that the European rabbit, (Oryctolagus cuniculi) was very sensitive to this virus, causing severe skin abscesses, infections, and ultimately death. In the 1950se, the myxomatosis virus was introduced and spread among wild rabbits in Australia, in order to reduce its population. This operation decimated almost all the wild rabbit population, except a few individuals that seemed resistant to this virus. The surviving rabbits started to reproduce offspring and colonized the country anew. In Europe, the virus spread rapidly and has now become endemic in some regions, which are populated by the European rabbit. The lagomorphï¿½s groups largely affected by the myxoma virus are the European rabbit (Oryctolagus cuniculi), the European hare (Lepus europaeus), the Brush cottontail (S. bachmani) and the eastern cottontail (S.

floridanus). Myxomatosis is caused by a virus belonging to the family of the Poxviridae, and is a type species of the genus Leporipoxvirus. The later comprises close related viruses that affect he American cottontail rabbit (Sylvilagus sp.) and the ï¿½hare fibroma virusï¿½, among others. All these viruses lead to the development of tumors of the skin connective tissues (fibroma). Various strains exist. Some are very virulent (e.g. Standard laboratory, Lausanne, California), others manifest their presence chronically. Genetic studies show a relationship between the myxoma and the Shope fibroma virus Blood sucking insects (fleas, mosquitoes, lice and mite) are efficient mechanical vectors of this disease. It was observed that the virus is present in the mouthï¿½s parts of the rabbit flea Spilopsyllus cuniculi, where it can survive over 100 days, independently of the environmental conditions. It is furthermore speculated that the disease may spread from one rabbit to another during skin and fur contact.

Left: Details of crusty lesions around the nose and the mouth Right: Swollen eye lid and purulent conjunctivitis Clinical signs The development of myxomatosis follows the typical pattern of a poxvirus infection. Once inoculated in the skin, the virus starts to reproduce in the skin and local lymph nodes. The virus is then spread through the body. The viruses are then spread throughout the body (viremia) and into the skin. The first evident signs of the disease appear 3 days after the infection: swelling (edema) of the eyelids, followed by the lips, genital organs and purulent conjunctivitis. At later stages of the disease, the rabbit becomes blind. The disease is usually fatal between day 8 to 15 after the infection with the virus. In the chronic form of the disease, the most prominent signs are the formation of skin tumors, called myxoma, on the ears, nose and limbs. These tumors will resorb by themselves after some time. A side effect of the chronic form of myxomatosis is the development of secondary bacterial infection. Pneumonia caused by Pasteurella sp. or Staphylococcus aureus is often observed.

It is accompanied by respiratory distress (dyspnea). Video: Myxomatosis (1): Clinical signs Diagnosis Although the disease depends on the strain of myxoma virus, it is usually severe and almost always fatal. The clinical symptoms are sufficient for diagnosis. One must keep in mind though, that early stages of the spirochetosis disease (caused by the parasite Treponema sp., affecting the perianal parts of the rabbit) look similar to those of myxomatosis. Indeed, tumors of those diseases show close similarities, so spirochetosis and myxomatosis must be carefully differentiated from each other. Myxomatosis should furthermore be differentiated from an upper respiratory infection, like e.g. Pasteurellosis. In the later, no swelling is observed in the perianal region, on the contrary to myxomatosis. In the case myxomatosis is chronic, it is recommended to do a biopsy and check it for the presence of viruses. ï¿½Treatment If a rabbit is affected by the aggressive form of myxomatosis, its chances of survival are close to zero. It is then recommended to humanely put the affected animal to sleep.

If treatment is chosen, intensive care over a longer period of time is needed. It is important to keep the sick rabbit in a warm environment (21-22ï¿½C). Eyes and ears must be regularly cleaned. As much fluids and food should be given to the rabbit as possible, even if the rabbit is drinking good amounts of water by itself. Skin tumors can be removed surgically. Unfortunately, secondary complications often appear. The most common one are respiratory disease and pneumonia, due to secondary infection by Pasteurella sp. or Staphylococcus sp. Rabbit that suffer a chronic form of myxomatosis recover by themselves. Antibiotics can be given to avoid respiratory complications. In regions where myxomatosis is endemic and present among the wild rabbit or cottontail population, prevention of the disease in pet rabbits is is possible by regular vaccination. This is not available in all countries. Video: Myxomatosis (2): Vaccination Depending on the vaccine used and the age or breed of rabbits, vaccinated rabbits may develop a mild to serious form of the disease. In rare cases, the rabbit must be put to sleep.

Denise Baart Bucks, a ï¿½3 years old male non-castrated dwarf rabbit, suffered from eye infections. It was unsuccessfully treated with Gentapolycort eye drops and Baytril (enrofloxacin). Bucks was then vaccinated against myxomatosis (Lyomyxovax). He apparently developed an allergic reaction to the vaccine. Ten days after the vaccination, a huge lump appeared on his back and he became blind. Blisters appeared around his eyes. Crusty dermatitis developed. As his condition kept worsening, Despite dedicated care by the veterinarian and the owners, his condition kept deteriorating and he was humanely put to sleep. ï¿½ A special thanks to Denise Baart, for sharing the pictures of her rabbit Bucks. Further Reading Best SM, Collins SV, Kerr PJ. Coevolution of host and virus: cellular localization of virus in myxoma virus infection of resistant and susceptible European rabbits. Virology. 2000; 277(1):76-91. Boag B. Observations on the seasonal incidence of myxomatosis and its interactions with helminth parasites in the European rabbit (Oryctolagus cuniculus).

J Wildl Dis. 1988; 24(3):450-5. Boag B, Lello J, Fenton A, Tompkins DM, Hudson PJ. Patterns of parasite aggregation in the wild European rabbit (Oryctolagus cuniculus). Int J Parasitol. 2001; 31(13):1421-8. Calvete C, Estrada R, Villafuerte R, Osacar JJ, Lucientes J. Epidemiology of viral haemorrhagic disease and myxomatosis in a free-living population of wild rabbits. Vet Rec. 2002; 150(25):776-82. Chapple PJ, Lewis ND. Myxomatosis and the rabbit flea. Nature. 1965; 207(995):388-9. Chapuis JL, Chantal J, Bijlenga G. Myxomatosis in the sub-antarctic islands of Kerguelen, without vectors, thirty years after its introduction. C R Acad Sci III.

1994; 317(2):174-82. Duclos P, Caillet J, Javelot P. Aerobic bacterial flora of the nasal cavity of rabbits. Ann Rech Vet. 1986; 17(2):185-90.ï¿½ Edmonds JW, Nolan IF, Shepherd RC, Gocs A. Myxomatosis: the virulence of field strains of myxoma virus in a population of wild rabbits (Oryctolagus cuniculus L.) with high resistance to myxomatosis. J Hyg (Lond). 1975; 74(3):417-8. Flowerdew JR, Trout RC, Ross J. Myxomatosis: population dynamics of rabbits (Oryctolagus cuniculus Linnaeus, 1758) and ecological effects in the United Kingdom. Rev Sci Tech. 1992; 11(4):1109-13. Fountain S, Holland MK, Hinds LA, Janssens PA, Kerr PJ.

Interstitial orchitis with impaired steroidogenesis and spermatogenesis in the testes of rabbits infected with an attenuated strain of myxoma virus. J Reprod Fertil. 1997; 110(1):161-9. Ghram A, Benzarti M, Amira A, Amara A. Myxomatosis in Tunisia: seroepidemiological study in the Monastir region (Tunisia). Arch Inst Pasteur Tunis. 1996; 73(3-4):167-72. Gorski J, Mizak B, Chrobocinska M. Control of rabbit myxomatosis in Poland. Rev Sci Tech. 1994; 13(3):869-79. Jiran E, Sladka M, Kunstyr I. Myxomatosis of rabbits--study of virus modification. Zentralbl Veterinarmed B. 1970; 17(3):418-28. Joubert L, Tuaillon P, Larbaigt G. Serologic and allergologic relationship between rabbit myxomatosis and fibromatosis viruses.

Conglutination reaction and homologous and heterologous hypersensitivity. Bull Acad Vet Fr. 1970; 43(6):259-76. Joubert L, Oudar J, Mouchet J, Hannoun C. Transmission of myxomatosis by mosquitoes in Camargue. Preeminent role of Aedes caspius and Anopheles of the maculipennis group. Bull Acad Vet Fr. 1967; 40(7):315-22. Kerr PJ, Merchant JC, Silvers L, Hood GM, Robinson AJ. Monitoring the spread of myxoma virus in rabbit Oryctolagus cuniculus populations on the southern tablelands of New South Wales, Australia. II. Selection of a strain of virus for release. Epidemiol Infect. 2003; 130(1):123-33. Kerr PJ, Best SM. Myxoma virus in rabbits. Rev Sci Tech. 1998; 17(1):256-68. Lawton MP. Myxomatosis vaccine. Vet Rec.

1992; 130(18):407-8. Licon Luna RM. First report of myxomatosis in Mexico. J Wildl Dis. 2000; 36(3):580-3. Marcato PS, Simoni P. Ultrastructural researches on rabbit myxomatosis. Lymphnodal lesions. Vet Pathol. 1977; 14(4):361-7. Marlier D, Mainil J, Linde A, Vindevogel H.ï¿½ Infectious agents associated with rabbit pneumonia: isolation of amyxomatous myxoma virus strains. Vet J. 2000; 159(2):171-8. Merchant JC, Kerr PJ, Simms NG, Robinson AJ. Monitoring the spread of myxoma virus in rabbit Oryctolagus cuniculus populations on the southern tablelands of New South Wales, Australia. I. Natural occurrence of myxomatosis. Epidemiol Infect. 2003; 130(1):113-21.

Merchant JC, Kerr PJ, Simms NG, Hood GM, Pech RP, Robinson AJ. Monitoring the spread of myxoma virus in rabbit Oryctolagus cuniculus populations on the southern tablelands of New South Wales, Australia. III. Release, persistence and rate of spread of an identifiable strain of myxoma virus. Epidemiol Infect. 2003; 130(1):135-47. Nash P, Barrett J, Cao JX, Hota-Mitchell S, Lalani AS, Everett H, Xu XM, Robichaud J, Hnatiuk S, Ainslie C, Seet BT, McFadden G. Immunomodulation by viruses: the myxoma virus story. Immunol Rev. 1999; 168:103-20. Omori M, Banfield WG. Shope fibroma and rabbit myxoma factories: electron microscopic observations. J Electron Microsc (Tokyo). 1970; 19(4):381-3. Patterson-Kane J. Study of localised dermatosis in rabbits caused by myxomatosis.

Vet Rec. 2003; 152(10):308. Patton NM, Holmes HT. Myxomatosis in domestic rabbits in Oregon. J Am Vet Med Assoc. 1977; 171(6):560-2. Regnery DC. The epidemic potential of Brazilian myxoma virus (Lausanne strain) for three species of North American cottontails. Am J Epidemiol. 1971; 94(5):514-9. Regnery DC, Miller JH. A myxoma virus epizootic in a brush rabbit population. J Wildl Dis. 1972; 8(4):327-31. Robinson AJ, Muller WJ, Braid AL, Kerr PJ. The effect of buprenorphine on the course of disease in laboratory rabbits infected with myxoma virus. Lab Anim. 1999; 33(3):252-7. Ross J. Myxomatosis and the rabbit. Br Vet J. 1972; 128(4):172-6.

Ross J, Tittensor AM. The establishment and spread of myxomatosis and its effect on rabbit populations. Philos Trans R Soc Lond B Biol Sci. 1986; 314(1167):599-606. Ross J, Sanders MF. The development of genetic resistance to myxomatosis in wild rabbits in Britain. J Hyg (Lond). 1984; 92(3):255-61. Ross J, Tittensor AM, Fox AP, Sanders MF. Myxomatosis in farmland rabbit populations in England and Wales. Epidemiol Infect. 1989; 103(2):333-57. Ross J, Sanders MF. Changes in the virulence of myxoma virus strains in Britain. Epidemiol Infect. 1987; 98(1):113-7. Rothschild M. Myxomatosis and the rabbit flea. Nature. 1965; 207(2):1162-3. Sellers RF.

Possible windborne spread of myxomatosis to England in 1953. Epidemiol Infect. 1987 Feb;98(1):119-25 Shepherd RC. Myxomatosis: the occurrence of Spilopsyllus cuniculi (Dale) larvae on dead rabbit kittens. J Hyg (Lond). 1978; 80(3):427-9. Shepherd RC, Edmonds JW. Myxomatosis: the release and spread of the European rabbit flea Spilopsyllus cuniculi (Dale) in the Central District of Victoria. J Hyg (Lond). 1979; 83(2):285-94. Sobey WR, Conolly D, Haycockp, Edmonds JW. Myxomatosis. The effect of age upon survival of wild and domestic rabbits (Oryctolagus cuniculus) with a degree of genetic resistance and unselected domestic rabbits infected with myxoma virus. J Hyg (Lond). 1970; 68(1):137-49. Sobey WR, Conolly D.

Myxomatosis: passive immunity in the offspring of immune rabbits (Oryctolagus cuniculus) infested with fleas (Spilopsyllus cuniculi Dale) and exposed to myxoma virus. J Hyg (Lond). 1975; 74(1):43-55. Torres JM, Sanchez C, Ramirez MA, Morales M, Barcena J, Ferrer J, Espuna E, Pages-Mante A, Sanchez-Vizcaino JM. First field trial of a transmissible recombinant vaccine against myxomatosis and rabbit hemorrhagic disease. Vaccine. 2001; 19(31):4536-43. Trout RC, Ross J, Fox AP. Does myxomatosis still regulate numbers of rabbits (Oryctolagus cuniculus Linnaeus, 1758) in the United Kingdom? Rev Sci Tech. 1993; 12(1):35-8. Werffeli F. Observations on the appearance of a clinically atypical manifestation of myxomatosis in wild and domestic rabbits. Schweiz Arch Tierheilkd.

1967; 109(1):9-16. Williams RT, Dunsmore JD, Parer I. Evidence for the existence of latent myxoma virus in rabbits (Oryctolaqus cuniculus (L.)). Nature. 1972; 238(5359):99-101. Wunderwald C, Hoop RK, Not I, Grest P. Myxomatosis in the rabbit. Schweiz Arch Tierheilkd. 2001; 143(11):555-8 Zuniga MC. Lessons in D tente or know thy host: The immunomodulatory gene products of myxoma virus. J Biosci. 2003; 28(3):273-85. Myxomatosis (Viral Disease) Sylvilagus brasiliensis - Tapeti Localised fibromas that may be up to several centimetres in diameter and are formed at the inoculation site. ( B209 .8.w8) The fibromas generally appear four to eight days after exposure and can persist for ten to forty days.

( B209 .8.w8, B611 .10.w10) There are no clinical signs of systemic disease in the adult rabbit but there may be the potential for this to occur in rabbits with immature immune systems. ( B209 .8.w8) Very young rabbits may succumb to generalised disease. ( B611 .10.w10) A firm localised fibroma may be found at the site of transmission (scratch, bite), often the ear base, lips, or feet. ( B209 .8.w8, B602 .19.w19, B609 .2.w2) The South American virus causes slightly more prominent lumps compared with the California strain. ( B611 .10.w10) The fibroma will eventually scab and regress over a period of weeks or months. ( B209 .8.w8) The fibromas may be the only clinical sign ( B602 .19.w19, B609 .2.w2); systemic disease or the prolonged persistence of the tumour is not seen, even in the young rabbit.

( B209 .8.w8) Common disease of Oryctolagus cuniculus - European rabbit ; occasional individual cases in Lepus europaeus - Brown hare . ( J514 .1.w1) Domestic pet rabbits, Oryctolagus cuniculus domesticus - Domestic European rabbit are much more susceptible to the myxoma virus than the wild cottontail rabbits, Sylvilagus spp. and also other rabbit species of North America. ( B609 .2.w2) Outdoor rabbits are possibly at greater risk due to the mode of the viral transmission. ( B609 .2.w2) Very young rabbits are particularly susceptible to infection and they will die quicker than adult rabbits unless they have a degree of passive immunity. ( B284 .10.w10, B600 .16.w16) Passive immunity can last for four to five weeks if there has been maternal transfer of antibodies. ( B284 .10.w10) Some wild Oryctolagus cuniculus - European rabbits may have a genetic resistance to myxoma virus infection.

( B284 .10.w10) Factors that affect survival include: The virulence of the strain of virus. ( B600 .16.w16) Intercurrent infection. ( B600 .16.w16) Environmental temperature: high (85�F) ambient temperature increases the recovery rate. ( B600 .16.w16) Other species: "Very intensive investigations have been done to determine the host range of the myxoma virus since this information was required by the Australian authorities before the decision could be made to release the virus. Numerous species of wild and domestic animals and birds were tested for susceptibility to the virus and ultimately it was shown that under natural conditions the myxoma virus would produce disease in leporids only". ( B611 .10.w10) Immunity in Oryctolagus sp. Antibodies are detectable from seven to ten days after infection and they will peak at around 28 days. ( B209 .8.w8, B600 .16.w16) Antibodies can persist for prolonged periods and may give absolute immunity for several months.

( B600 .16.w16) Antibodies can persist for a minimum of two years and most likely for the life of the animal. ( B209 .8.w8) European rabbits that have recovered from this disease are considered immune for life. However, there are reports of possible recrudescent infections or of reinfection. ( B209 .8.w8) Most UK wild rabbit populations have some immunity to this virus now. ( B603 .3.w3) Maternal transfer of antibodies: Maternal antibodies will cross the placenta and persist for six to eight weeks in the young; the antibodies can provide limited protection from myxomatosis that is transmitted by mosquitoes. ( B209 .8.w8) Maternal antibodies will give baby rabbits four to five weeks of immunity. ( B600 .16.w16) Paternal resistance: there is possibly some immunogenic factor in semen. Bucks mating within seven months of infection with myxomatosis may confer partial resistance to the progeny born within the following seven months.

( B600 .16.w16) Genetic resistance Some rabbits possess a genetic resistance to the myxoma virus and it has been a limiting factor in the mortality rates in some outbreaks in wild rabbits. The resistance varies between different rabbit populations and countries. British rabbits were slower to develop resistance compared to the Australian rabbits. ( B284 .10.w10, B600 .16.w16) Immunity in Sylvilagus- (Genus) This has not been extensively investigated in Sylvilagus brasiliensis - Tapeti . In Sylvilagus bachmani - Brush rabbit , neutralising and complement-fixing antibodies have both been detected but are relatively short lived. Although the Californian and South American strains of myxoma virus cause a lethal disease in Oryctolagus cuniculus - European rabbit , Sylvilagus brasiliensis - Tapeti (found in Central and South America) is resistant to the lethal effects of the Californian virus and Sylvilagus bachmani - Brush rabbit (North America) is resistant to the Brazilian virus. Transmission via insect vectors Transmission via blood-feeding insects is a major transmission route.

( J514 .1.w1) Transmission occurs when the vector probes through the epidermis of a lesion on an infected animal. The virus particles in the lesion will adhere to the vector's mouthparts and are then inoculated into the next host when the vector feeds. ( B209 .8.w8) Any insect that penetrates the skin when it is biting / feeding on the host, may transmit the disease. ( B600 .16.w16) Non-biting insects may act as mechanical vectors of myxoma virus ( B609 .2.w2): The source of the virus is often the superficial layers of skin particularly eyelids and ear bases where even arthropods that feed on the surface of the skin (e.g. mites and lice) may act as mechanical vectors of the virus. ( B611 .10.w10) There is no viral replication within the vector so there is not a virus-vector specificity. ( B209 .8.w8) The difference in the life cycle of the insect vectors in various parts of the world results in differences in epidemiology. ( B600 .16.w16): Mosquitoes Aedes spp.

including Aedes aegypti , Aedes scapularis, or ( Anopheles ) spp. ( B611 .10.w10) Myxomatosis will spread rapidly via mosquito vectors and there is likely to be a high seasonal incidence of disease. ( B600 .16.w16) Pet rabbits that are housed in hutches are easily exposed to myxomatosis via mosquitoes. ( B600 .16.w16) Fleas Fleas ( Siphonaptera (Order) ) are an effective vector of this disease because: they may maintain the infectivity throughout the winter months and therefore act as a good reservoir of infection for the following year; ( B284 .10.w10) their life cycle is actually synchronised with the doe's reproductive status and therefore results in heavy infestations of susceptible neonates. ( B284 .10.w10, B600 .16.w16) The flea is an effective reservoir of the myxoma virus as it has a far longer life span compared with mosquitoes (active female mosquitoes live for two to three weeks; fleas can feed actively for over a year).

It has been shown that the virus may persist for 105 days in rabbit fleas that are held in artificial burrows that have no rabbit contact. ( B611 .10.w10) Therefore, fleas are able to maintain infectivity throughout the winter months even in the absence of hosts and then they will provide a reservoir of infection for the subsequent year. ( B600 .16.w16) In parts of the world where fleas are the primary vector of myxomatosis (e.g. UK), disease outbreaks are often quite localised with only isolated pockets of infection. Myxomatosis will only be seen sporadically in pet rabbits. ( B600 .16.w16) Rabbit fleas, Spilopsyllus cuniculi, are commonly involved. ( B603 .3.w3) They can be introduced to a domestic rabbit kept by itself by "hitchhiker" fleas on predators like the domestic cat or the fox. ( B603 .3.w3) Cat or dog fleas, Ctenocephalides felis or canis respectively.

( B603 .3.w3) Flies Transmission by flies ( Diptera ) may also occur. ( B602 .19.w19, B604 .5.w5, B609 .2.w2) Calypterid flies such as Musca ( Muscidae - (Family) ), Calliphora and Lucilia ( Calliphoridae - (Family) ) etc. pose a lower risk of viral transmission as they do not inoculate the virus intradermally. ( B603 .3.w3) Fur mite Food ( B609 .2.w2) Birds' feet ( B602 .19.w19) Claws of predatory birds and also carrion feeders (e.g. crows: Corvus spp. and buzzards) have been shown to be contaminated with myxoma virus and in Sweden it has been proposed that such birds may play a role in the dissemination of myxoma virus. ( B611 .10.w10) Transmission via direct contact or inhalation Myxomatosis can be spread directly between rabbits because the virus is also shed in discharges (e.g.

ocular discharges or oozing from skin lesions). ( B209 .8.w8, B600 .16.w16, B602 .19.w19, B603 .3.w3, B611 .10.w10, J514 .1.w1) This is quite a rare method of transmission. ( B601 .13.w13) Most domestic rabbit outbreaks occur through indirect or direct contact with wild rabbits, rather than domestic rabbit to domestic rabbit spread. ( B603 .3.w3) Some strains can undergo respiratory transmission. ( B209 .8.w8) Fluid from myxomatosis lesions will contaminate hutches that have housed infected rabbits. The virus will persist in this environment and will be able to infect unvaccinated rabbits that subsequently use the hutches. ( B600 .16.w16) Windborne transmission is suspected. ( J213 .4.w4) Transmission in different countries Principle natural vectors: are thought to be mosquitoes of the Aedes (Genus) .

( B611 .10.w10) California The first dose is given from 6 weeks of age. ( B600 .3.w3, B601 .13.w13) Boosters: every 6-12 months depending on perceived risk. ( B601 .13.w13) If there is a high risk of myxomatosis in the local area or the pet rabbit is potentially exposed to wild rabbits that are infected with myxomatosis or insects, then vaccinate every six months; if there is no obvious local risk then perhaps only vaccinate annually in spring to cover the main risk period. ( B600 .3.w3, B603 .3.w3) Note: in some areas myxomatosis may be actively transmitted year round. ( V.w121 ) Absence of obvious wild rabbits with myxomatosis in an area does not necessarily mean absence of myxomatosis in the area.

( V.w121 )mean Optimum time for vaccination: MYXOMATOSIS ~ DIAGNOSIS and TREATMENT | bunniesinneed.net MYXOMATOSIS ~ DIAGNOSIS and TREATMENT HOW IT IS DIAGNOSED In making a diagnosis, pathologists frequently take a sample from the mucous membranes of the conjunctiva and examine tissue with a microscope for the presence of intracytoplasmic inclusion bodies in infected cells. The presence of these inclusion bodies, along with clinical signs as indicated above, is used to make the diagnosis. The diagnosis of myxomatosis is made through observing the clinical signs, biopsies of the lesions, and virus isolation. In many cases, because the rabbit dies suddenly, the diagnosis is made post-mortem (after death). TREATMENT ~ each of the following three statements represent the opinions of different sources There is no effective treatment for myxomatosis Progress of the disease may be slower in well cared for pet rabbits and recovery is sometimes possible with intensive care. However, myxomatosis can be a very protracted and profoundly unpleasant disease and euthanasia is generally recommended.

There is no specific treatment for myxomatosis so only supportive care (fluids, antibiotics to prevent secondary infections, etc.) can be offered. However, because domestic rabbits tend to be very susceptible to the virus and tend to suffer a long and painful death, euthanasia is often recommended to prevent suffering. More info here ~ ~ the content has not been copied into this topic because doing so has been specifically prohitibed. Sources ~ *********** Meadow speaking ~ HERE IS THE ONLY RAY OF TREATMENT HOPE ABOUT WHICH I AM AWARE ~ This article is from a letter Dana Krempels, Ph.D. had on “All Experts” and was sent to me by another bunny. The author of the treatment experience is a veterinarian in Australia.

“Hi Dana I’m forwarding this to you (with the author’s permission), as it just might be something to keep on file should you hear of anyone in Australia or California who have a rabbit with myxi who is not vaccinated (the product referred to is not on the market in the UK, so it doesn’t really help the UK) It may be something, may be nothing, but it is an interesting observation, and might be useful if anyone did want to try treating a non-vaccinated bunny with myxi…. our vets usually recommend euthanasia as soon as the diagnosis is made, as results are so poor despite intensive treatment and suffering great along the way, but opinions differ. Do pass it to anyone who may find it interesting.” THE LETTER FROM THE VET ~ “I am a vet in Australia. I am writing to tell you of an interesting success I have had in treating my bunnies that caught myxi. I had three bunnies and a 12 month old hare that I reared. One bunny I euthanised after 13 days with Myxi symptoms, the hare died.

The second bunny that had symptoms, Littlebunny, I was nursing and dosing 3-4 times daily with a witches brew of vits (vitamins), antioxidants, immune stimulants, etc. and giving sub q fluids and antibiotics. He lost significant weight and was having to mouth breathe (making it too risky to orally medicate anymore) by three weeks into the disease. He was a mass of lesions distorting eyes and nares (nasal passages), and his body and genitals were covered in lesions. At this time my third bunny, Bigbunny, had symptoms for 4 days – swollen reddened eyes with a number of lesions on lid margins and ears.

At this point I thought of trying the Vetrepharm product, Equimune IV, a acterial cell wall fraction immune-stimulant registered in Australia for treatment of Equine Respiratory Tract Infections of viral origin, but used off-label here for things like FIV (Feline immunodeficiency virus), demodex (a genus of tiny parasitic mites that live in or near hair follicles of mammals), parvo (Parvovirus, all strains will affect dogs, wolves and foxes; but only some will affect cats) , prostate cancer, bladder tumours, and other debilitating conditions in small animals. I gave my bunnies 0.25ml IV into lateral ear vein once weekly. Littlebunny was pretty debilitated at the start of this treatment but while not showing any improvement, he remained in good spirits, continued to eat and did not lose any more weight. I did continue his Baytril s/c in courses of 10 days broken by 5-7days. He required no other time consuming nursing apart from cleaning and medicating eyes bid (twice a day).

Today he is 10-11 weeks with the disease and in the last 10 days the lesions have been shrinking and falling off eyelids. He has gained a little weight and despite still being a bit snuffly, I think is on the mend. I believe without Equimune I would have had to euthanise him before end of 4th week. Bigbunny is the big excitement- there was no progression of symptoms from the commencement of treatment with Equimune. His eye lesions may have reddened a little some days but for the most settled down and certainly there was no spread. He never skipped a beat and was a happy unaffected fat bunny throughout – maybe a few sniffly days but pretty much a walk in the park. By 4-5th week his eye lesions were resolving and he was a normal bunny. Neither of my bunnies have been vaccinated for myxi – the vax (vaccine) not avail in Australia. It is no scientific trial by any means but it would appear that caught early with Equimune, Bigbunny didn’t develop full blown symptoms. And I know Littlebunny would not be alive without those weekly injections.

The Vetrepharm rep tells me injections at 10 day intervals would have been sufficient and probably only 4 injections necessary. I guess I will still continue the injections for Littlebunny until all lesions and respiratory signs are gone. Vetrepharm is a Canadian company – you can find it on the web and get info on their products: Regressin-V, Immunoboost, Equimune IV. We only have the Equimune in Australia I think. The rep tells me they have cured Bladder tumours in dogs infusing it by urinary catheter, cured prostate cancer in dogs, cured a doberman with a malignant melanoma in the chest, cured a cat with FIV. I have had good results in a pup with parvo. I think the website : will give distributor info in UK. I think it is worth trying and considering there was no intensive nursing necessary – just good housing and food, it is a cheap treatment, especially if my bunnies are now with good immunity to meet future challenge as good or better than being vaxd (vaccinated).

In my funny way of thinking- if this success (Bigbunny’s experience) is repeatable it might be better to take bunnies to a myxi party and treat with equimune than annual vaxs – like my mother did with us as kids to get things like chickenpox and measles. I only have 2 bunnies and pet bunnies are prohibited in my State so I can’t call for other bunnies with myxi to do a proper trial. And I would never deliberately infect bunnies with myxi for experiment anyway. I might be able to get a vet in another state to call for bunnies with myxi to test this treatment.”

Question: Myxomatosis is a viral disease affecting which creatures?
Answer: Rabbits